How should a 70‑year‑old woman with left T2‑T3 herpes zoster treated with a 7‑day course of valacyclovir who now has left intrinsic hand muscle weakness due to segmental zoster paresis be managed?

Management of Segmental Zoster Paresis Following Herpes Zoster

For a 70-year-old woman with left T2/T3 herpes zoster who has completed 7 days of valacyclovir and now presents with left intrinsic hand muscle weakness due to segmental zoster paresis, extend antiviral therapy beyond the initial 7-day course and continue treatment until complete clinical resolution, add corticosteroids if not contraindicated, initiate gabapentin for neuropathic pain control, and begin immediate physical therapy with range-of-motion and strengthening exercises. 1, 2

Extend Antiviral Therapy

The standard 7-day valacyclovir course is insufficient when neurologic complications develop. 1

• Continue valacyclovir 1000 mg three times daily until all lesions have completely scabbed and neurologic symptoms stabilize, as treatment duration should be guided by lesion healing and clinical response rather than an arbitrary 7-day endpoint. 1

• If lesions remain active or new neurologic deficits are progressing, consider escalation to intravenous acyclovir 10 mg/kg every 8 hours, particularly given her age and the presence of motor complications. 1, 3

• Monitor renal function closely during extended antiviral therapy, with dose adjustments as needed for any renal impairment that may develop. 1

Add Corticosteroid Therapy

Corticosteroids combined with antivirals may provide benefit in acute herpes zoster with motor complications, though the evidence is mixed. 4

• Initiate prednisolone 40 mg daily, tapering over 3 weeks (e.g., 40 mg for 1 week, 30 mg for 1 week, 20 mg for 1 week, then discontinue), as this regimen has been studied in acute herpes zoster and may reduce acute-phase pain and inflammation. 4

• Screen for contraindications including poorly controlled diabetes, severe osteoporosis, active infection, or history of steroid-induced complications before initiating corticosteroids. 1

• The rationale is that segmental zoster paresis likely results from inflammation and viral spread to motor neurons; corticosteroids may reduce this inflammatory component. 2

Initiate Neuropathic Pain Management

Gabapentin is the first-line agent for acute neuropathic pain associated with herpes zoster. 1

• Start gabapentin and titrate in divided doses up to 2400 mg per day (e.g., 300 mg three times daily initially, increasing by 300 mg every 2-3 days as tolerated). 1

• Counsel the patient that somnolence occurs in approximately 80% of treated individuals, so dose escalation should be gradual and the patient should avoid driving or operating machinery until tolerance develops. 1

• Continue analgesics (acetaminophen, NSAIDs) for acute pain relief during the initial phase. 1

Begin Immediate Physical Therapy

Early physical therapy is critical to prevent contractures and optimize functional recovery in segmental zoster paresis. 2

• Initiate daily inpatient physical therapy if the patient is hospitalized, or three times per week outpatient therapy if managed as an outpatient, focusing on range-of-motion exercises for the affected shoulder and hand. 2

• Include strengthening exercises for the intrinsic hand muscles and any other affected muscle groups as tolerated. 2

• Set realistic expectations: partial improvement is typical, with recovery often incomplete even after 2 months of therapy. 2

Diagnostic Confirmation and Monitoring

Segmental zoster paresis is a clinical diagnosis, but additional testing helps exclude alternative causes and document the extent of involvement. 2

• Electrophysiological studies (EMG/NCS) can confirm motor involvement in the myotome corresponding to the affected dermatome and help differentiate from other causes of upper extremity weakness. 2

• Cervical MRI should be obtained to exclude structural lesions (e.g., disc herniation, tumor, epidural abscess) that could mimic or coexist with segmental zoster paresis. 2

• Cerebrospinal fluid analysis may show pleocytosis and elevated protein, supporting the diagnosis of VZV-related neurologic involvement, though this is not always necessary if the clinical picture is clear. 2

Prognosis and Follow-Up

Recovery from segmental zoster paresis is variable and often incomplete. 2, 5

• Most patients experience partial improvement over 2-6 months, but complete recovery is uncommon, particularly in proximal muscle groups like the deltoid. 2

• Schedule monthly follow-up to assess motor function, pain control, and functional status. 2

• Consider long-term suppressive gabapentin if neuropathic pain persists beyond the acute phase, as postherpetic neuralgia is common in this age group. 1

Vaccination After Recovery

Once the patient has fully recovered from the acute episode, strongly recommend the recombinant zoster vaccine (Shingrix) to prevent future recurrences. 1

• Shingrix provides >90% efficacy in preventing future herpes zoster episodes and is recommended for all adults aged ≥50 years, regardless of prior herpes zoster episodes. 1

• Administer the two-dose series (0 and 2-6 months) after complete resolution of the current episode. 1

Common Pitfalls to Avoid

• Do not discontinue antiviral therapy at exactly 7 days if lesions have not completely scabbed or if neurologic complications are present; treatment should continue until clinical resolution. 1

• Do not delay physical therapy while waiting for complete pain resolution, as early mobilization is critical to prevent contractures and optimize functional recovery. 2

• Do not attribute all upper extremity weakness to segmental zoster paresis without excluding other causes (cervical radiculopathy, brachial plexopathy, stroke) through appropriate imaging and electrodiagnostic studies. 2

• Do not use corticosteroids in immunocompromised patients or those with poorly controlled diabetes without careful risk-benefit assessment, as the risks may outweigh benefits. 1